I already ran scannow and it completed with no errors. Very strange that this one particular update won't install when all the others do. Incomprehensible. Now I know why people buy Apple computers. You have to be a masochist to keep banging your head against some of these opaque Windows walls. I guess I are one. ;-)

Not sure I want to waste an hour doing a repair install. This doesn't seem like a truly important update (something to do with daylight savings time) so I think I'll just ignore it for now.

My latest successful update was Hotfix for Windows (KB947821). Yes, all other updates are installed including the ones you listed. Strange, though, that (KB979538) originally failed on 9/30 but then installed successfully on 10/1.

There are no other failed installs other than the first attempt at (KB979538) and the ongoing issue (KB2158563).

Ran Belarc... there's a ton of info in the report. But the top line says "Virus protection" and "Windows security updates" are up to date and have green checkmarks. The list of Win7 updates looks similar to what control panel reports and (KB2158563) is missing in both.

Thanks for looking at this JC. I was aware that I had a couple of unintended restarts last week but since I wasn't in front of the PC so I didn't realize they were BSODs. With your observation that the bugcheck hints that this might be hardware related I downshifted the system from it's mild overclock to eliminate that variable. I am also going to update my BIOS to the latest this evening.

Then I tried a system restore and that didn't work. So I took your first advice and did a repair install and that seems to have fixed the problem. That troublesome DST update, and all the rest, completed successfully. Only real issues were that it hosed up my Norton installation (anti-virus could not be turned on for some reason after the Windows repair install) so I did a regular Windows uninstall of Norton then reinstalled it. It's working well again.

I'll run it like this awhile before pulling the string further on potential hardware BSOD issues. Perhaps it's all good now [fingers crossed]. But if it was a hardware issue I wonder what on earth it could have done to prevent Windows from installing the odd update? Corrupted some file or other?